This invention pertains to improvements to a solar water heater.
It involves a solar water heater which heats and stores water through direct passage that does not include a water exchanger and which acts as a compact unit that performs and which is economical.
The sought-after goal according to the invention is to construct an efficient solar water heater at a low cost, which is compact, and that does not require ancillary equipment, which is insensitive to frost, and that can be set up with excellent performance regardless of the region, whether cold, mild or tropical.
The solar water heater, which is the subject of the invention, is of the kind that includes a storage tank which is located inside the transparent structure. According to the invention, the storage tank is mounted inside a transparent structure which is completely sealed, and is resistant to atmsopheric pressure. An intermediate narrow space for a vacuum is provided, between the tank and the outer structure, at least two hydraulic water input and output connections connect the storage tank to the outside of the water heater crossing in sealed fashion the outer structure, and at least two series of spacers are arranged between the tank and the structure, and are located towards the two ends of the tank which sustain the structure of said vacuum space.
This overall concept provides a water heater having very substantial benefits compared to the water heaters of the prior known art. These benefits basically come from the excellent thermal insulation of the inner tank that is housed inside a glass structure which is not very far from the outer wall of the tank and inside which structure a high vacuum exists. However, such a construction raises many technical problems that this invention enables to resolve under the best circumstances.
In particular, in conformance with this invention, hollow or protruding housings are formed inside the inner wall of the outer structure in order to accommodate at least some of the spacers. This prevents rotation in one direction and translational motion in both directions of the tank inside the glass structure, which makes it possible to work on the unit in one rotational direction during welding of caps that close the ends of the structure and also guarantees blocking a translational motion of the tank inside the structure which facilitates the transportation of the heater.
According to another characteristic of the invention, at least one bottom of the inner tank is concave, which facilitates the operations of closing the structure surrounding the tank, and also enables savings in clearance volume.
According to another characteristic of the invention, the water inlets and outlets from the tank are installed with elastic connections, which limits the expansion constraints that might be exerted on the glass structure.
The invention also refers to a method for manufacturing the water heater which includes various successive implementation stages.